People don't usually buy an intake for massive gains, because there are none. It's mostly for the sound.

True, most people do buy them for the sound, but some gains are still there.

I'm not very familiar with the older M50s , but in the newer M54s some intakes can provide 0 hp gain some as much as 6rwhp and some can make you even lose HP. All been proven and backed by numerous dynos.

I would suspect the same could be said for the older M50s, but I might be wrong.